The main objectives of the Baylor Center for Cerebrovascular Research are to improve knowledge in living subjects by non-invasive means, concerning the anatomy, physiology, patholoy, biochemistry, pathogenesis, natural history, diagnosis, prevention and treatment of cerebrovascular disease and to differentiate them from changes that accompany physiological aging. These changes will be measured by a series of indices, some already available, some to be developed. Measurements include cerebral blood flow (CBF) by 133Xe inhalation, computerized transmission tomography (CT scan) following high dose intravenous contrast infusion so that the cerebral and cerebrovascular anatomy may be visualized, electroencephalography (EEG) and neuropsychological testing including automated behavioral assessment devices. The effect of behavioral activation, sleep and changes in end-tidal PECO2 on CBF will be evaluated in both normal volunteers and patients with cerebrovascular disease. The effects of risk factors for atherothrombotic stroke (hypertension, diabetes, hyperlipidemia, smoking and heart disease) on the normal decline of CBF with age will be determinnd and compared with symptomatic patients (TIAs, strokes, multi-infarct and related dementias). The effects of medical treatment by control of risk factors and surgical treatment (carotid endarterectomy STA-MCA by-pass) will be evaluated. In stroke models such as the baboon, the time course and nature of diaschisis and the influence of treatment will be examined along with the relation of endema and seizures to the time course of CBF and CTs. In suitable models the effect of ischemia on the physiology of membrane function and ionic movement will be investigated. The possible protective or enhancing effects on cerebral atherogenesis of different ratios of high density to low density lipoproteins will be determined. It is hoped to develop harmless screening methods whereby a cerebrovascular aging quotient may be developed which on comparison with chronological age will be an accurate predictor of those at risk from stroke and who may require preventive measures or treatment.